Soft tissues, such as ligaments, tendons and muscles, are attached to a large portion of the human skeleton. In particular, many ligaments and tendons are attached to the bones which form joints, such as shoulder and knee joints. A variety of injuries and conditions require attachment or reattachment of a soft tissue to bone. For example, when otherwise healthy tissue has been torn away from a bone, surgery is often required to reattach the tissue to the bone to allow healing and a natural reattachment to occur.
A number of devices and methods have been developed to attach soft tissue to bone. These include screws, staples, cement, suture anchors, and sutures alone. Some of the more successful methods involve use of a suture anchor to attach a suture to the bone, and tying the suture in a manner that holds the tissue in close proximity to the bone. The tissue may be attached to the bone during open surgery, or during closed (e.g., arthroscopic) surgical procedures. While many conventional suture anchors are successful in anchoring tissue to bone, they suffer from some disadvantages as well. For example, many conventional suture anchors provide small passageways through which the suture must be threaded, causing difficulties or delays in threading the suture. Moreover, attachment of the suture thread to the anchor, typically at the distal end of the anchor, can result in disadvantageous movement or twisting of the suture thread. Where two free ends of suture thread are required or desired, unwanted tangling and knotting may occur when two suture ends exit the anchor through a single hole in the anchor body or on the same side of the anchor body. Other disadvantages can result where the anchor is a screw-type anchor. For example, the suture thread can be abraded or otherwise damaged when the anchor is threaded into bone. Further, once the anchor is implanted, slidable movement of the suture thread is often prevented.
Accordingly, there remains a need for an improved system for anchoring soft tissue to bone.